Today looks rough: weather pushes the average chance of arriving 15+ min late to 58%, against 41% on a calm day. Safest: WN 4015 at 20:35, 58%.

Safest bet today WN 4015 TPA 20:35 → DAL 22:05 · 58% chance 15+ min late · usually 45% on time Riskiest WN 2459 TPA 16:51 → DAL 18:33 · 58% chance 15+ min late

Weather 58% average chance a nonstop arrives 15+ min late; 41% for the same flights on a calm-weather day

Every nonstop today

12-month record →

Ranked by the chance of arriving 15+ minutes late, with each flight’s on-time record over Aug 2025 – Jul 2026 beside it. Times are local. Pick a flight for its forecast. Click a column to sort. 4 flights that already left today are not shown.


WN 4015 Southwest Flight history →	TPA 20:35	DAL 22:05	58%	19%	1.0%	45%
WN 4151 Southwest	TPA 20:36	DAL 22:18	58%	19%	1.0%	no record
WN 2459 Southwest	TPA 16:51	DAL 18:33	58%	11%	0.8%	no record

How these are worked out. Each flight’s odds are our forecast for that day; flights of airlines we don’t forecast yet use their 12-month record and are marked. Makes the connection: the first flight’s 12-month lateness curve, scaled so its chance of arriving 15+ min late matches the day’s forecast, at the layover minus the 45-minute minimum (90 on separate tickets). Arrives on time: first flight not cancelled × connection made × second flight not cancelled × second flight within 15 minutes, each from the day’s forecast.

About this data: forecast odds from our model for Sun, Oct 4 (newest published update); 12-month records from US DOT on-time data, Aug 2025 – Jul 2026, all US airlines; regional flights count under the airline that sells them. JSON